1. Field of the Invention
This invention relates to an improvement of an internal combustion engine exhaust brake control device for use in conjunction with an automatic transmission. In particular, the invention relates to the addition of switch means actuated by the manual down-shifting of the transmission which automatically energizes the exhaust brake device.
2. Description of the Prior Art
An internal combustion engine exhaust brake device is known as a means of creating exhaust back pressure to impart a braking action on the engine.
The exhaust brake device is generally used to increase the braking effect of the decelerating engine of a diesel engine vehicle. By placing a valve in the exhaust pipe or manifold which, when activated, impedes the flow of the engine exhaust gas, a back pressure is created in the exhaust system of the engine that imparts a braking action on the piston.
The prior art exhaust brake devices are activated by means of a manual switch which has to be actuated by the driver and a throttle switch which is generally connected to and actuated by the accelerator pedal.
Operation of conventional exhaust brakes requires the vehicle operator to actuate the manual switch on each occasion that the exhaust brake is necessary, such as when the vehicle commences a descent down a slope. When the exhaust brake is no longer needed, the conventional system requires the operator to deactivate the manual switch. The necessary manual manipulation of the exhaust brake switch is inconvenient and can be hazardous.
The present invention alleviates the frequent necessity of manually activating and deactivating the exhaust brake. The exhaust brake is most frequently used in addition to down-shifting an automatic transmission. By providing a means of automatically activating the exhaust brake on manually down-shifting the transmission, the added step of manually activating the exhaust brake is eliminated except where the brake is used without down-shifting. In addition, the present invention eliminates the necessity of deactivating the exhaust brake on the frequent occasions where it will have been automatically activated by transmission down-shifting. The switch means which automatically activates the exhaust brake also deactivates the brake on manually shifting from the lower gears to "drive."